Vista - When User Account Control is enabled, Vista Games Explorer won't s

We have Vista home premium, and 3 user accounts, 1 admin and 2 restricted
users for my wife and son. My account works fine, no issues, but both my wife
and son now can't play games, or even open the Vista Games Explorer window.
As soon as they click the icon to launch it, the window flashes for a second,
then closes. Trying to launch these games (solitaire, mine sweeper, chess) by
directly clicking on the shortcut or executable causes the cursor to flash
for a second, then nothing. No errors are displayed, and I haven't found any
indication of problem.
I tried changing my wife's account to and administrator, but that didn't
work. But... When I disabled User Account Control and rebooted, the problem
went away. I re-enabled it, rebooted, and the problem came back. Also, I do
get an error logging into my wife's account indicating that "People Near Me"
couldn't start due to permissions problems.

So, I suspect a problem with security settings of some sorts, but I don't
know my way around Vista well enough to know where to start troubleshooting.